Staging: dgnc: fixed coding style issue in digi.h

Fixed coding style issue "warning line over 80 characters"
detected by checkpatch.pl in digi.h

Signed-off-by: Buţiu Alexandru Octavian <predator5047@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>